1. Field of the Invention
The present invention relates to a liquid crystal display (LCD) module, and more particularly to an LCD module employing a flexible printed circuit (FPC) instead of a gate or source driver printed circuit board (PCB). Portion of the PCB or FPC corresponding to the respective thermocompression bonded tape carrier packages (TCP) is substantially decreased to reduce the thermal expansion difference between PCB and TCP.
2. Description of the Related Art
Recently, an LCD as a data display device is gaining its importance as the information display device becomes smaller and lighter.
A cathode ray tube (CRT) that has been most widely used has lots of advantages in terms of function or price. However, there still exists a problem of size or portability. An LCD has an advantage in size, weight, and power consumption and is now rapidly replacing the CRT.
In a general LCD module, input electrode patterns of gate drive TCPs are connected correspondingly to the connector pads of a gate drive PCB while output electrode patterns are connected correspondingly to the pads for connecting a gate line of an LCD panel. In addition, input electrode patterns of source drive TCPs are connected correspondingly to the connector pads of a source drive PCB while output electrode patterns are connected correspondingly to the pads for connecting a data line of an LCD panel.
A gate drive PCB and a source drive PCB are electrically connected by an FPC so as to accomplish a rapid signal transmission.
However, in a conventional art, the gate portion and the source portion are both made of an PCB, which causes some problems.
First, the side portion of the LCD module becomes thick. As a result, the weight of the LCD module increases. This is against the tendency toward a slim device.
Moreover, a device for connecting the source portion and the gate portion is needed which complicates the assembly and increases manufacturing costs. That is, the gate drive PCB and the source drive PCB are respectively connected to the pads for connecting a gate line of an LCD panel and to the pads for connecting a data line of an LCD panel, and are interconnected by an FPC. For example, an FPC is soldered to a gate drive PCB, and is connected to a source drive PCB by being inserted into a terminal block fixed onto the source drive PCB. Thus, additional processes for the soldering and inserting into the terminal block are required. In addition, an FPC for connection is needed, thus increasing manufacturing costs.
Meanwhile, the gate drive PCB and the source drive PCB are respectively connected to the pads for connecting a gate line and to the pads for connecting a data line of an LCD panel, by inserting TCP. As is widely known, a driving IC is mounted onto the TCP. In a conventional LCD panel, the connector pads and TCP are connected by a thermocompression bonding method employing an anisotropic conductive film while PCB and TCP are connected by soldering. However, as the number of input pins of the driving IC increases and TCP size decreases, a pin pad pitch is required to be decreased. If PCB and TCP are connected by soldering in such a structure, a short may occur between the adjacent pins.
Recently, thermocompression bonding at a high temperature is employed for a connection between PCB and TCP. However, a misalignment or a warpage of TCP may be caused due to a difference between the coefficients of the heat expansions of PCB and TCP. As a result, product""s reliability with respect to assembly, vibration or impact may be harmed. This problem becomes worse when the PCB size increases as the screen size becomes larger and when the PCB becomes thin as the LCD module becomes slim. To overcome these problems, there has been proposed a structure where two PCBs are interconnected. However, an additional connector is required for a signal transmission. Such an increase in the number of PCBs causes a more complicated manufacturing process and higher costs.
It is therefore an object of the present invention to provide a slim and lightweight LCD module.
It is another object of the present invention to provide an LCD module with less number of manufacturing processes, lower costs and a simplified assembly process.
It is still another object of the present invention to provide an LCD module in which any misalign or a warpage of TCP may not occur when TCP and PCB are thermocompression bonded so as to be interconnected.
In accordance with an aspect of the present invention, a source drive portion facing either of the neighboring edges in a lower portion of the LCD panel is connected to a lower panel by a TCP on which a source driving integrated circuit (IC) is mounted. A gate drive portion facing another edge is connected to the lower portion of the LCD panel by a TCP on which a gate driving IC is mounted and is electrically connected to the source drive portion. One of the source or gate drive portions is made up of FPC while the other is made up of PCB.
TCP connector pads are respectively disposed by a predetermined space along the edges to which the gate and source drive portions face, and the source and gate drive portions are interconnected by an FPC connector portion formed integrally with either of the source and gate drive portions.
For example, an FPC connector pad is formed at an end portion of the FPC connector portion, and can be connected to PCB by a conductive adhesive. In addition, the FPC connector pad is inserted into a terminal block of the PCB so as to be connected to the other side of the PCB.
Preferably, electronic components generating an electrical signal for the gate driving IC are mounted to one of the source drive portion or the gate drive portion that is made up of PCB.
In accordance with another aspect of the present invention, there is provided an LCD module including an LCD panel, and a gate-source integrated type drive FPC facing the neighboring edges of the lower portion of the LCD panel and where a source drive portion connected to the lower portion of the LCD panel by a TCP on which a source driving IC is mounted and a gate drive portion connected to the lower portion of the LCD panel by a TCP on which a gate driving IC is mounted, are integrally formed.
Here, the electronic components generating an electrical signal to be applied to the gate and source driving IC are directly mounted to the gate and source drive portions of the gate-source integrated type drive FPC. Preferably, such electronic components can be mounted by a flip-chip bonding.
In accordance with yet another aspect of the present invention, an LCD module of the present invention includes a source drive FPC which faces either of the neighboring edges in the lower portion of the LCD panel and is connected to the lower portion of the LCD panel by a TCP on which a source driving IC is mounted, and a gate drive FPC which faces the other edge of the neighboring edges and is connected to the lower portion of the LCD panel by a TCP on which a gate driving IC is mounted. The source and gate drive FPCs are respectively connected to the graphic interface devices having electronic components for generating the electrical signal applied to the source and gate driving ICs.
For example, the source and gate drive FPCs are connected to the graphic interface device by a conductive adhesive, or are inserted into the terminal block of the graphic interface device so as to be connected to the graphic interface device.
In accordance with further another aspect of the present invention, an LCD module of the present invention includes a source drive portion that faces either of the neighboring edges in the lower portion of the LCD panel and is connected to the lower portion of the LCD panel by a TCP on which a source driving IC is mounted, and a gate drive portion that faces the other edge of the neighboring edges and is connected to the lower portion of the LCD panel by a TCP on which a gate driving IC is mounted and is electrically connected to the source drive portion. The TCPs are connected to the source and gate drive portions by a thermocompression bonding. At least one means for substantially decreasing the size of the area by which the TCPs are attached to the source and gate drive portions, is formed in the source and gate drive portions.
A separating slot formed at edges of the source and gate drive portions that face the lower portion of the LCD panel can be used as such means for decreasing the size of the area.
Preferably, length of the separating slot is longer than that of the area by which the TCP is attached to the drive portions. In addition, the separating slots are more likely formed densely at the edges of the source and gate drive portions rather than at the center.
As an embodiment of the present invention, there is provided an LCD module including: an LCD panel having an upper panel and a lower panel that is attached to the upper panel by filling a liquid crystal between the upper and lower panels; a source drive portion that faces either of the neighboring edges of the lower panel, and is connected to the lower panel by a first connector portion having a source driving IC and that is formed integrally with the source drive portion; and a gate drive portion that faces the other edge of the lower panel, and is connected to the lower panel by a second connector portion having a gate driving IC and that is formed integrally with the gate drive portion, and is electrically connected to the source drive portion. Either of the source or gate drive portion is made up of FPC.
For example, the source and gate drive portions are formed integrally with each other. Preferably, the first and second connector portions are separated into driving IC units by the respective separating slots.